Refrigerating shelf structure



May 21, 1963 L. F. BARRoERo 3,090,211

REFRIGERATING SHELF STRUCTURE Filed Feb. 27, 1961 4 Sheets-Sheet 1 May 21, 1963 L. F. BARRoERo REFRIGERATING SHELF STRUCTURE:

Filed Feb. 2 7, 1961 heets-Sheeit 2 ||||||III IIIII.

FIIIIIIII'IIII INVENTOR.' 0a/5 /1' A/ZQOEBO A TTENE YS' May 21, 1963 L. F. BARROERO 3,090,211

REFRIGERATING SHELF STRUCTURE FildFeb. 27, 1961 4.Sheets-Sheet 3 INVENToR.- 0a/5 E neogeo BY www A TTOAIVE Ys May 21, 1963 L. F. BARROERO 3,090,211

REFRIGERATING SHELF STRUCTURE Filed Feb. 27, 1961 4 Sheets-Sheet 4 INVENToR:

` 0a/s F. 5.4220520 A fm2/ms United States Patent O 3,090,211 REFRIGERATING SHELF STRUCTURE Louis F. Barroero, 1585 Daniels Drive, San Leandro, Calif.

Filed Fel). 27, 1961, Ser. No. 91,939 17 Claims. (Cl. 62-256) This invention relates to refrigerating display cabinets and more especially to a compartmentalized refrigerating shelf structurer as shown in my recently Iissued United States Patent No. 2,962,875.

Subsequent to `my invention of the compartmentalized shelf structure and refrigerating apparatus of United States Patent No. 2,962,875, I discovered that unusual and unexpected benefits were obtained by operating a series of divided shelf structures so as to pass refrigerated air upward from the upper compartment of one shelf into the bottom compartment of the superjacent shelf. rIlhe refrigerated 'system which I originally devised circulated air downward through the shelf structures as shown and described in Patent No. 2,962,875, 'but in so doing and as a result thereof, substantial amounts of lcondensate collected upon the associated foods fand produce. While this result is of lmaterial importance and advantage in refrigeriating certain produce, such as fresh vegetables, it is entirely unsatisfactorily where freezing temperatures are to be maintained and under other conditions where moisture is objectionable. Although various attempts have been made to control and eliminate the Iformation of condensate, such attempts were generally unsuccessful until while experimenting with the original apparatus the direction of air llow was reversed.

There is no apparent reason Why Ia mere change in air flow direction should eliminate the formation of condensate. Although various air ow `systems have been previfously employed for `circulating air in a vertical ilouv, and even for moving air upwardly as opposed to downwardly, none of those systems contemplated or expressed the difference in results that is obtained with the type of compartmentalized shelf Structure here involved. This is attributable to the fact that none of the prior art refrigerating structures utilized the form of shelf :structure and system as taught by my earlier patent No. 2,962,875.

It has been noted, in retrospect, that United States Patent No. 2,862,369 teaches `an air refrigerating structure having compartmentalized shelf structures. However, the shelf structures therein contemplated do not utilize the concept of passing refrigerated air through the shelf space between lower and upper shelves, but, rather, utilize a turbulent air ow within the spaces between shelves. With such a structure it would apparently make little -or no difference as rto the direction :or manner by which the refrigerated air Iwas passed into or removed from the shelf spaces, since a turbulent air ilow involves both upward and `downward air column movements.

As an outgrowth of my discovery and further development, I have invented a novel formof refrigerating shelf structure and support therefor which may be used in the type of duct air system as taught by Patent No. 2,962,875. Since this `system involves a fluid communication between shelf structures and at least two duct passages, and since at least one passage opening must he provided into an upper compartment and at least one passage opening into a lower compartment of each shelf, there has been some difficulty in maintaining la relative thinness in the shelf structures and yet providing sufficiently large passage openings to efficiently conduct the necessary amount of circulated air. Furthermore, inasmuch as my earlier invention provided air passage openings !and duct leads that were unsymmetrical relative to the peripheral edge of the shelf as a whole, it was impossible to utilize the duct lead passages interchange- 3,0%,Zll Patented May 21, i963 ably. It rwas previously necessary, therefore, to provide two types of lair ducts, `one type -for opening at a height matable with a bottom shelf compartment inlet and another type having openings matable with an upper shelf compartment inlet at a slightly more elevated height and within an elevational difference of one-half the shelf thickness. However, the present invention contemplates a shelf structure and duct arrangement utilizing a single form of yair duct that can be used for both upper and lower compartments, thereby effecting substantial savings in the Icost of manufacture, storage and replacement. Additionally, in view of my recent discovery, it is of particular advantage to circulate air from an upper compartment of a flower shelf into the lower compartment of an upper shelf, as -well as to provide a reverse air circulatin-g system so as to move air from a lower compartment to an upper compartment. inasmuch as the shelf structures herein contemplated are provided with symmetrically formed openings which are centered relative to top and bottom surfaces, they may be interchangeably employed yfor both types of air llow systems.

Another feature of this invention involves providing a refrigerating cabinet structure of the kind described with compartmentalized shelf `structures supported from vertical duct members. Additionally, the shelf structures are so -formed that their rear edges extend rearwardly into alignment .with the 'back edge of the supporting duct members. This allows the [full depth of the cabinet structure to be utilized for refrigeration, and it is then unnecessary to provide an additional width for the duct members in back `of the shelves, as required and shown by my earlier U.S. Patent No. 2,962,875.

It is to .be understood that one object of this invention is to provide a novel method for circulating :air within a refrigerated compartment, whereby refrigerated air is moved vertically upward through a perforated support surface, exhausted through perforations in a superjacent surta-ce, and then recycled While being refrigerated.

Another object is to provide apparatus for carrying .out the above descibed method and including compatmentalized shelf structures` and means for moving refrigerated yair `from the upper compartment of one shelf into the lower :compartment of a super-jacent shelf.

A further object of the invention is to provide a refrigerating and compartmentalized shelf structure having inlet Iand outlet duct openings formed symmetrically in its peripheral edge.

An additional object is to provide guide vanes within -a compartmentalized shelf structure for distributing air currents .to remote pockets `or regions, thereby producing a more uniform temperaturer throughout the shelf space.

Another object of the invention -is to provide guide vanes Within la compartmentalized shelf structure for exhausting lair from all pockets and regions therewithin, thereby producing more uniform exhaust pressures and eliminating stagnant yair pockets within the shelf cornpartment and from between adjacent shelves.

Another object is to provide a compartmentalized and refrigerating shelf structure having corner edges with duct leads formed therein, saidl corner edges extending angularly forward from a rear edge, and including means for iiuidly communicating said duct leads to a vertical air duct, whereby said rear edge of said shelf is in approximate alignment with the back side of each air duct. l

Other objects of this invention will become apparent in view of the drawings and the following detailed description.

In the drawings forming a part of this application and in which like parts are identified by like reference numerals throughout the same,

FIG. 1 is a front elevation of a preferred embodiment for a refrigerating cabinet and shelf structure formed in accordance with the principles of this invention, the front enclosure side of a refrigerating chamber having been removed to illustrate operational details;

FIG. 2 is a section taken on lines 2 2 of FIG. l to illustrate various surfaces of the shelf structures;

FIG. 3 is a side elevation of the cabinet and shelf structure shown in FIG. 1;

FIG. 4 is a perspective view of the preferred form of shelf structure with lid surface removed as utilized with the cabinet structure shownA in FIGS. 1-3;

FIG. 5 is a section taken on lines 5 5 of FIG. 4;

FiG. 6 is a section taken on lines 6 6 of FIG. 4;

FIG. 7 is a side elevation of a support arm for a shelf structure, illustrating its mounting arrangement with a vertical air duct;

FIG. 8 is a broken section through a shelf structure and supporting air ducts showing its mounting and the fluid connections therebetween;

FIG. 9 is a detail of an alternative form of sealing means for iluidly communicating a shelf structure to an air duct; and

FIG. 10 is an isometric view of another form of shelf structure.

Referring to lFIGS. 1-3 of the drawings, there is shown a free standingopen front access refrigerating cabinet structure 10 comprising a plurality of compartmentalized shelves 11 and 12 supported from means defining air duct passages 13, 14, 15 and 16. Shelves 1l and 12 are similar to one another, however they possess duct lead connections to opposite air compartments within the shelves as will be more clearly demonstrated. The cabinet structure 10 is framed at either end by enclosure panels 17 and 1S that may be formed of insulating inaterial, and a series of slidable rear door panels 19, 20 and 21 provide selective access to the shelves from the rear. Cabinet structure 10 also provides an enclosed air compartment 22 within which a coil 23 refrigerates recycled air, said air being moved under static pressure by pushpull blowers 24 and 25, respectively.

Although cabinet structure 10 is shown as a free standing unit, it is to be understood that such structures, or other structures having similar features, could be set into Iwall recesses. Moreover, :the feature of self containing refrigerating apparatus is not an essential part of the cabinet structure and it is contemplated that a remote refrigerating source for recycled air might also be employed.

Each shelf structure 11 and 12 is divided into upper and lower air compartiments by an imperforate member 26. The upper supporting surface of each shelf as well as its bottom surface is provided with perforated openings 8 (including slotted openings Sa in the upper supporting surface) to allow the passage of air vfrom the upper compartment of one shelf upward 'through a shelf space and into the lower compartment of the superjacent shelf. Suicient openings are provided and arranged to produce substantially rectilinear air flow in the same general manner disclosed by my US. 'Patent No. 2,962,- 875. However, it is important that the direction of air ow be from a lower to its superjacent shelf in order to der-ive the benefits of a moisture free refrigerating cabinet structure, as now contemplated.

Duct passages 13 and 15 are connected Vto a manifold passage 27, which is acted upon by the exhausting iniluence of blower 25; and passages 14- and 16 fluidly oommunicate with a manifold passage 28 through which refrigerated air is moved under the static pressure supplied by blower 24. In view of the drawings, it will be seen that refrigerated air is continuously cycled from compartment 22 through manifold 28, into duct passages 14 and y 16, through the upper air compartment of each shelf, then through the refrigerated shelf space into the lower compartment of a superjacent shelf and returned via duct passages 13 and 15 into compartment 22.

The shelf surfaces may be provided with various arrangements of openings or perforations 8 and, of course, some arrangements operate better than others. Inasmuch as some new air is drawn into the refrigerated forced air system from the open front and side accesses, and since this new air tends to warm merchandise along the peripheral 4edges of the shelf, it is desirable that more refrigerated air should be moved through the regions of open front and side access than, for example, through the middle of the shelf. Therefore, the openings along the peripheral edge of a shelf structure may be formed as louvers 8a to allow more passage of air therethrough than is allowed to pass through the center regions. The principle of selective arrangement of openings is believed to be obvious in view of and contemplated by my earlier patent No. 2,962,875. Moreover, no matter what ar rangement of openings is provided, the principle of moving air currents vertically through a shelf space and between adjacent shelves remains the same.

FIGS. 4-6 illustrate a preferred form of shelf structure 1-1 most clearly. Each shelf structure has duct leads 29 and 30 formed in its peripheral edge, one duct lead connecting to the lower air compartment and a second duct lead leading to the upper air compartment. The passageways between said duct leads and their respective compartments are defined by inclined ramps 31a and 311;, respectively, which block off the opposite compartment. It will be evident that both duct leads are formed symmetrically relative to the shelfs periphery, each duct lead bein-g of equal size and shape and substantially centered relative to top and bottom shelf surfaces. This construction enables the duct lead openings to be approximately the same `size in depth as .the thickness of the shelf, thereby enhancing the movement of air current lto and from each shelf structure. It will also Ibe noted that Athe duct leads 29 and 30 are provided in the rearmost corners of the shelf, and the corner peripheral edges 32 and 33 extend angularly forward from the rearmost edge portion 34. The duct leads project angularly rearwardly with respect to their corner edges but run generally parallel with the sides of the shelf, as shown in FIG. 2. Therefore, each shelf is matable and is adapted to be mated with the vertical duct passages Iby merely moving them rearwardly from the front of the cabinet structure. But, in addition, the illustrated construction provides a shelf structure having a refrigerated shelf `space which extends clear back to the rear-most reference plane 35 as defined by the air ducts shown in FIG. 2. This provides greater economy of space in back lof the cabinet structure while sacrificing very little shelf space. Another material advantage is that the air duct passages are themselves disposed within the columnar movement of refrigerated air currents rather than exposed on three sides to air currents of normal room temperature. Should the duct passages -13-16 be disposed rearward of the shelf spaces, moisture would tend to collect on the surfaces of the duct passages.

As a further improvement, a series of ow guide vanes 36 and 37 is provided adjacent each duct lead. It has been found that such vanes are extremely useful in distributing cold air to all areas of ythe shelf, placing the interior air compartments under more uniform static and exhaust pressures and contributing to a rectilinear air flow between adjacent shelves.

A strengthening support frame 38 is provided within the upper compartment of each shelf so as to prevent buckling of the upper lid. Frame 3S is comprised of transverse members which span between sides of the shelf and over the imperfora-te member 26.

It is to ebe understood that shelf structures 11 and 12 are substantially the same in form, shape and structure. However, since the duct passage 14 is connected tothe right duct lead of shelf structure 11 and the left duct lead of shelf structure 12 (the opposite relationship existing as between duct passage 15 and its associated duct leads), it should be apparent that the lead connections to the upper and lower air compartments must be reversed if both shelves are to pass air vertically in the same direction. Inasmuch as .the duct leads 29 and 30 of shelf structure 1v1 are symmetrical relative to the peripheral edge, the direction of the ramps is reversed in the process of manufacturing a shelf lstructure 12.

It is contemplated that shelf structures .11 and 12, being symmetrical, might be used with opposite duct passages in the event that a downward air flow should be desired. As explained above, if the air currents between shelves are moved downwardly rather than upwardly, moisture will tend to collect upon the supported produce; and this result is desirable `for refrigerating fresh vegetables and the like. Importantly, it is to be understood that the same shelf structures, constructed in the manner herein contemplated with symmetrical duct lead openings, can be effectively used in refrigerated systems where the air is moved upward or downward through shelf spaces between shelves.

FIGS. 1 3 and 7-9 illustrate a particularly useful means for supporting shelf structures 11 and 12 from means dening the duct passages and for sealingly interconnecting the duct -leads to those passages. Each shelf structure is supported by a pair of spaced army brackets 39, and the arm brackets are -detachably mounted Ato the air duct passage means. angle member 40 or a T-channel 41 is attached Ito the front side of the duct means. Pin members 42 are secured to the angle member 40 and -to both sides of the T-channel 41, as shown, said pins extending horizontally and being disposed in vertically spaced pairs. 'Ihe arin brackets are formed with an upper hook 43 for engaging with the uppermost pin and having a lower recess 44 for engaging the lowermost pin. Also, arm brackets Y 39 have a laterally extending ledge 45 for supporting one side of a shelf. It will be understood that such an assemblage as thereby provided may be easily disassembled for cleaning. Moreover, although no threaded attachments are necessary, each shelf structure will be properly supported in a position for connection to the associated duct passage.

PIG. v8 also illustrates a type of fluid seal that may be provided to join the duct leads 29 and 30 to their respective air duct passages. A peripherally slotted sealing ring 46, preferably made lfrom resilient material, is secured -to each opening into the duct passages. Rings 46 define a cylindrical opening for receiving the duct leads of a shelf as it is moved rearwardly upon the support brackets 39.

In FIG. 9 there is shown another sealing arrangement that might be used wherein a sealing ring 47 is provided as part of the duct leads of the shelf structures. This is structurally the reverse of the form of sealing means shown in FIG. `8 and would require a modified form of shelf duct lead from that illustrated in FIGS. 4-6. Nevertheless, in both forms of sealing rings the duct lead connections are completed merely by moving the shelves rearwardly upon 4their supporting arm brackets.

FIG. 10 illustrates another form of shelf structure 111. It will be noted that duct leads .112. and L13 are also symmetrically formed relative to the peripheral shelf edge, and that inclined passages are defined by ramps l.1;14 and 115, such as to interconnect the duct lead openings to lower `and upper air compartments, respectively. Thus, this shelf structure also has many of the same advantages outlined above in connection with a description of the shelf shown in FIGS. 4-6. However, it will be evident that the duct passages with which it would connect would be entirely to the rear of the shelf space. Such an arrangement would, therefore, increase the As best illustrated in FIG. 8, an

available shelf space but at a sacrifice of space in the rear. Moreover, the air duct passages would tend to collect moisture unless insulated, if exposed to room atmosphere. But in installations having a refrigerated rear air vault enclosing each air duct passage, the possible disadvantages would not he noticed.

It is to be realized that the particular embodiments shown and described are to be taken as preferred examples of the invention, and that various changes in the shape, size and arrangement of parts may be resorted to Iwithout departing from the spirit of the invention or the scope of the attached claims, and each of such changes in contemplated.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. An open access refrigerating apparatus comprising:

(a) a hollow refrigerator support shelf having substantially horizontal upper and lower perforated surfaces and an imperforate member therebetween dividing said support shelf into an upper static pressure chamber and a lower exhaust chamber,

(b) means defining a static pressure chamber having a substantially horizontal upper perforated supporting surface disposed subjacent to the lower perforated surface of said support shelf and vertically spaced therefrom to define a shelf space therebetween, the lower surface of said support shelf vertically overlying the upper supporting surface of the static pressure means with openings of each surface providing an upward directional tiowpassage for refrigerated air,

(c) means deiining an exhaust pressure chamber having a substantially horizontal lower perforated surface disposed superjacent to the upper perforated surface of said support shelf and vertically spaced therefrom to define a shelf space therebetween, the lower surface of said exhaust pressure means Vertically overlying the upper surface of said support shelf with openings of each surface providing an upper directional flowpassage for refrigerated air.

(d) air circulating means comprising a refrigerated air plenum, an. air pressure manifold communicating the static pressure chamber of said support shelf and the static pressure means with said refrigerated air plenum, an air exhaust manifold communicating the exhaust pressure chamber of said support shelf and the exhaust pressure chamber means with said refrigerated air plenum, and blower means for forcing refrigerated air under static superatmospheric pressure into said air pressure manifold and exhausting air under subatmospheric pressure from said air exhaust manifold, said blower means being of suiiicient capacity to produce a substantially vertical and upward movement of air through said shelf spaces while maintaining articles disposed within said shelf spaces in flowstreams of refrigerated air, the portions of said flowstream within which said articles are disposed being pressurized above the atmospheric pressure of air surrounding the refrigerating apparatus.

2. The refrigerating apparatus of claim 1 and further wherein said hollow refrigerating support shelf includes guide varies disposed within said upper static pressure chamber for directing air flows from the air pressure manifold communicating therewith into remote regions of said static pressure chamber and placing said remote regions under substantially uniform satic pressures.

3. The open access refrigeratitng apparatus of claim l and further including guide vanes disposed within the exhaust chamber of said hollow support shelf for controlling the application of exhaust pressures applied thereto by said exhaust manifold communicating therewith to evacuate remote interior regions of said exhaust chamber.

4. An open access refrigerating apparatus comprising:

(a) a refrigerator support shelf providing means defining a static pressure chamber and an exhaust chamber, and having substantially horizontal upper and lower perforated surfaces, the upper surface having openings communicating with said static pressure chamber and the lower surface having openings communicating with said exhaust chamber,

(b) means defining a static pressure chamber having a substantially horizontal upper perforated supporting surface disposed subjacent to the lower per- Vforated surface of said support shelf and vertically spaced therefrom to denne a shelf space therebetween, the lower surface of said support shelf vertically overlying the upper supporting surface of the static pressure means with -openings of each surface providing an upward directional How passage for refrigerated air,

(c) means defining an exhaust pressure chamber having a substantially horizontal lower perforated surface disposed superjacen-t to the upper perforated surface of said support shelf and vertically spaced therefrom to define a shelf space therebetween, the lower surface of said exhaust pressure means vertically overlying the upper surface of said support shelf with openings of each surface providing an upper directional flow passage for refrigerated air,

(d) air circulating means comprising a refrigerated air plenum, an air pressure manifold communicating the static pressure chamber of said support shelf and the static pressure means with said refrigerated air plenum, an air exhaust manifold communicating the exhaust pressure chamber of said support shelf and the exhaust pressure chamber means with said refrigerated air plenum, and blower means for forcing refrigerated air under static superatmospheric pressure into said air pressure manifold and exhausting air under subatmospheric pressure from said air exhaust manifold, said blower means being of sufficient capacity to produce a substantially vertical and upward movement of air through said shelf spaces while maintaining articles disposed within said shelf spaces in flow streams of refrigerated air,

the portions of said fiow stream within which said articles are disposed being pressurized above the atmospheric pressure of air surrounding the refrigerating apparatus.

5. A refrigerating shelf structure for use with a duct air system of the kind described having both inlet and exhaust duct passages, said shelf structure having top and bottom surfaces and a peripheral edge, and comprising: means defining upper and lower air compartments separated by an imperforate member, a first opening into said upper compartment and a second opening into said lower compartment, said first and second openings being formed lin the peripheral edge and symmetrically formed of equal size and shape and substantiaily centered relative to top and bottom surfaces, means defining an inclined passage leading from said first opening to said upper compartment, and means defining an inclined passage leading from said second opening to said lower compartment.

6. The refrigerating shelf of claim and further including a set of guide vanes disposed within said upper and lower compartments and adjacent said openings.

7. A refrigerating shelf structure for use with a duct air system of the kind described having both inlet and exhaust duct passages, said shelf structure having top and Vbottom surfaces and avperipheral edge including a rear edge portion and first and second corner portions extending angularly forward therefrom, and comprising: means defining upper and lower air compartments separated by an imperforate member, a first opening formed in said first corner portion fluidly communicating with said upper compartment and a second opening formed in said second corner portion Yfluidly communicating with the lower compartment.

8. A refrigerating shelf lstructure for use with a duct air system of the `kind described having both inlet and exhaust duct passages, said shelf structure having top and bottom surfaces and ya peripheral edge including a rear edge portion and first and secon-d corner portions extend-v ing angular-ly forward therefrom, and comprising: means defining upper and lower -air compartments separated by an imperfonate member, a firs-t opening formed in said first corner portion tluidly communicating with said upper compantment and a second opening formed in said second corner portion iiuidly communicating Wit-h said lower cornpartment, said first Iand second lopenings being formed symmetrically of equal size and shape `and substantially centered relative `to top `and bottom surfaces, means delining yan inclined passage ieading from said first opening to said upper compantment, land means defining an inclined passage 4leading from said second opening to said lower compartment.

9. The refrigerating shelf of claim 8 and further including 4a set of guide vanos disposed within said upper and llower compartments and adjacent said openings.

10. Air circulating lapparatus 'of the kind described and comprising: a pair of spaced vertical air ducts each air duct having a ventical Ismfaoe diverging forwardly with respect lto a rear vertical reference plane, said surfaces defining ycorner contours for a shelf structure, each surface having a duct opening for the passage of air therethnough; a refrigena-ting shelf structure for use with said pair of spaced air ducts, said shelf structure having top` land bottom Ksurfaces and a peripheral edge including first and second corner portions extending angular-ly forward from a rear edge portion, said corner portions being complements of said air duct surfaces, respectively, and being positionable opposite to .said duct openings, said shelf structure including means idefining upper and lower air compartments sepa-rated by an irriperfonate member, a first opening formed in said rst corner portion fluid-ly communicating with said upper compantrnent and a second opening formed in said second corner portion fiuidly communicating with said lower compartment; means for supporting said lshelf from said air ducts when said shelf openings are in :abutting relationship to said air duct openings; and means for fluidly connecting said shelf :openings to said air duct openings, respectively.

1l. The air circulating apparatus of claim l0 wherein said means for fluidly connecting said shelf Iopenings to said air duct openings comprises a duct ilead formed circumferentially of one opening of each mat-ing pairs of openings, said other opening of each pair being provided with a sealing gasket.

12. The lair circulating Iapparatus of claim l0 wherein said means for supporting said lshelf from said air ducts comprises a pair of vertically spaced pins mounted horizontally from each air duct; `and a pair of removable shelf arm brackets, each having a ledge for supporting one side of said :shelf Eand also including an upper 'hook for engaging the uppermost pin Iof a pair of said pins and a lower recess for engaging the 'lowermost pin.

13. Air circulating apparatus |of the kind described and comprising: -a pair `of horizontally spaced vertical air ducts, each air duct having horizontally aligned duct openings for the passage of air therethrough; a refrigerating shelf structure for use with said pair of spaced air ducts, sai-d shelf structure having top 'and bottom surfaces and a peripheral rear edge positifonable opposite to said duct openings; said shelf structure including means defining upper :and lower air compantments separated Aby yan imperforate member, a rst opening into said upper compartment fand a @second opening into said lower compartment, said openings being formed in the peripheral edge and symmetrically formed .of equal size and shape and substantially centered relative to top and bottom surfaces; means defining an inclined passage 'leading from said first 9 opening -to Ksaid upper compartment, means defining an inclined passage Ileading from said second opening rto said lower compartment; means for supporting said shelf from said Iair ducts when said shelf openings are in abutting relationship `to said air duet openings; and means for fluidly connecting shelf openings to mated air duet openings.

14. The fair circulating apparatus of claim 13 wherein said means for supporting said shelf from said air duets comprises ra pair of vertically spaced pins mounted horizontally from each air duct; Vand a pair of removable shelf arm brackets, each having 'a ledge for supporting one side of said shelf and also including an upper hook for engaging the uppermost pin of a pair of said pins and a lower recess for engaging the `lovvermost pin.

15. A refrigerator shelf structure for use with a duct air system, said shelf structure having top and bottom surfaces and a peripheral edge, `and comprising: means denn-ing upper and lower air compartments separated by an .imperio-rate member, first and second openings being formed in the peripheral edge :and each opening being substantially centered relative to top and bottoni surfaces, and means communicating said rst opening with said upper compartment and said second opening with said lower compartment.

16. The refrigerating shelf fof claim 15 land further including guide wanes Idisposed Within said upper compartment for directing air Hows from said first opening into remote regions `of said compartment and placing said remote regions under substantially uniform static pressures.

17. rThe rerigerating shelf of claim 15 and further including guide vianes disposed Within said tiower coinpartment for controlling the application of exhaust pressures through vsaid second Iopening to evacuate remote interior regions of said lower compartment.

References Cited in the file of this patent UNITED STATES PATENTS 

15. A REFRIGERATOR SHELF STRUCTURE FOR USE WITH A DUCT AIR SYSTEM, SAID SHELF STRUCTURE HAVING TOP AND BOTTOM SURFACES AND A PERIPHERAL EDGE, AND COMPRISING: MEANS DEFINING UPPER AND LOWER AIR COMPARTMENTS SEPARATED BY AN IMPERFORATE MEMBER, FIRST AND SECOND OPENINGS BEING FORMED IN THE PERIPHERAL EDGE AND EACH OPENING BEING SUBSTANTIALLY CENTERED RELATIVE TO TOP AND BOTTOM SURFACES, AND MEANS COMMUNICATING SAID FIRST OPENING WITH SAID UPPER COMPARTMENT AND SAID SECOND OPENING WITH SAID LOWER COMPARTMENT. 